When do dropdowns automatically populate?

There are times when a columns dropdown will automatically populate.

I’ve noticed this at times but never really spent time on understanding it. As I build out an app, I often find that dropdowns that at one time had values become empty and I need to add an appropriate expression in the Valid_If.

Under what conditions are dropdowns automatically populated without the need of an expression?

When data already exists, and you have these options checked:
image

That doesn’t seem to be the whole story.

I have a Ref column with no expressions (except Initial value) and it is showing all possible values from the referenced table. I’m pretty sure I have implemented others where this didn’t happen and I was forced to add an expression. Maybe something has changed recently?

In another post by another developer, a column is defined with an EnumList/Ref type and the two properties you mentioned are checked but zero values show in the dropdown. Caveat: I am depending on the screenshots and that they are showing the correct columns and dropdowns.

I assumed you were only referring to Enum type, with my above response.

Yes a Ref column will automatically pull in all possibilities from the Ref’d table if no valid_if is defined.

Enum w/ Ref type does NOT pull in the possibilities from the Ref’d table. In this case you need to provide a valid_if.

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Does the usage of Slices make a difference?

A Ref column pointed at a slice will only provide the possible records from that slice.

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